CN113394059B - Multi-pole multi-throw switch based on RF MEMS switch - Google Patents

Abstract

The invention relates to a multi-pole multi-throw switch based on an RF MEMS switch, which includes: a substrate; two MEMS single-pole multi-throw switches arranged on the substrate and cascaded; the MEMS single-pole multi-throw switch includes several signal lines and ground wires , several upper electrodes, several driving electrodes, power dividers and several air bridges. By cascading two MEMS single-pole multi-throw switches, this multi-pole multi-throw switch can not only reduce the insertion loss of the device, improve the isolation of the device, reduce the size of the device, and broaden the operating frequency of the device, but also The gating function of multi-channel signals can be realized.

Description

A multi-pole multi-throw switch based on RF MEMS switch

Technical field

The invention belongs to the field of radio frequency MEMS technology, and specifically relates to a multi-pole multi-throw switch based on an RF MEMS switch.

Background technique

The RF MEMS (Micro-Electro-Mechanical System) switch is a MEMS passive device. Its main working principle is to control the opening and closing of the upper electrode by driving the electrode, thereby controlling whether the signal is conductive. Compared with traditional mechanical and electronic switches (divided into PIN and FET), RF (Radio Frequency, radio frequency) MEMS switches have the advantages of small size, light weight, low power consumption, small insertion loss, high isolation, frequency With the advantages of good bandwidth, linearity and high integration, it is easy to integrate with microwave devices, such as phase shifters, filters, antennas, etc., and can realize a variety of functions.

Domestic RF MEMS switch research institutions include Tsinghua University, Northwestern Polytechnical University, China Power Group 13th Institute, China Power Group 55th Institute and other units. A radio frequency MEMS switch and its formation method announced by Tsinghua University use a cantilever beam as the upper electrode, and a copper film plus graphene as the switch contact, effectively solving the problem of high temperature caused by gold-gold contact causing switch failure; China Power Group Fifty The Fifth Institute announced a monolithic integrated multi-band control MEMS switch, which consists of three series contact MEMS switches and can achieve single-channel signal conduction.

At present, no domestic institution has published research on multi-pole multi-throw switches based on MEMS technology. Existing MEMS switch research can only achieve single-channel signal conduction and cannot achieve multi-channel signal gating function.

Contents of the invention

In order to solve the above problems existing in the prior art, the present invention provides a multi-pole multi-throw switch based on an RF MEMS switch. The technical problems to be solved by the present invention are achieved through the following technical solutions:

The embodiment of the present invention provides a multi-pole multi-throw switch based on an RF MEMS switch, including:

substrate;

Two MEMS single-pole multi-throw switches arranged on the substrate and connected in cascade;

The MEMS single-pole multi-throw switch includes a number of signal lines, a ground line, a number of upper electrodes, a number of driving electrodes, a power divider and a number of air bridges, wherein the number of signal lines and the number of driving electrodes are distributed on the substrate. on the surface of the bottom, the ground wire is located on the substrate and is provided on both sides of the signal lines and on the peripheral side of the driving electrode, the power splitter is provided on the substrate, and the power splitter is provided on the substrate. The splitter includes a plurality of first branches and a second branch, the plurality of first branches and the second branches form a star structure, the plurality of first branches are connected to each of the signal lines, and two of the MEMS single-pole The multi-throw switch is connected through the second branch, an end of each driving electrode is located between each signal line and the power divider, and each upper electrode is provided on the power divider. And simultaneously located above each of the signal lines and each of the driving electrodes, two of the MEMS single-pole multi-throw switches are connected through the power splitter, and each of the air bridges is located on the surface of the ground wire and cross across the signal lines.

In one embodiment of the present invention, the number of the signal lines, the number of the upper electrodes, and the number of the driving electrodes are all four.

In one embodiment of the present invention, the signal line adopts a bending structure at the crossing position of the air bridge.

In one embodiment of the present invention, the upper electrode includes an upper electrode cantilever beam, a first anchor point, at least two contacts and a first release hole array, wherein,

The first anchor point is disposed on the power splitter, the at least two contacts are disposed on the signal line at intervals, and the upper electrode cantilever beam is disposed on the first anchor point and located on the Above the contact point, the first release hole array is distributed on the upper electrode cantilever beam.

In one embodiment of the present invention, the first release hole array includes a plurality of first release holes distributed in an array, the number of rows of the first release hole array is 1 to 6 rows, and the number of columns is 1 to 8 columns, the spacing of the first release holes in each row or column is 4-8 μm, and the diameter of each first release hole is 4-10 μm.

In one embodiment of the present invention, the driving electrode includes an electrode, a lead wire and a bonding pad, wherein,

The electrode is located between the end of the signal line and the power splitter and below the cantilever beam;

One end of the lead-out wire is connected to the electrode, and the other end is connected to the pad.

In one embodiment of the present invention, the electrode has a convex-shaped structure, and the protruding portion of the convex-shaped structure is located between the contacts.

In one embodiment of the present invention, the air bridge includes a fixed cantilever beam, a second anchor point, a third anchor point and a second release hole array, wherein,

The second anchor point is provided on the ground line and is located on one side of the signal line. The third anchor point is provided on the ground line and is located on the other side of the signal line. A support cantilever beam is disposed on the second anchor point and the third anchor point to cross the signal line, and the second release hole array is distributed on the fixed support cantilever beam.

In one embodiment of the present invention, the second release hole array includes a plurality of second release holes distributed in an array, the number of rows of the second release hole array is 1 to 6 rows, and the number of columns is 1 to 12 columns, the spacing of the second release holes in each row or column is 6-10 μm, and the diameter of each second release hole is 6-10 μm.

Compared with the existing technology, the beneficial effects of the present invention are:

By cascading two MEMS single-pole multi-throw switches, the multi-pole multi-throw switch of the present invention can not only reduce the insertion loss of the device, improve the isolation of the device, reduce the size of the device, and broaden the operating frequency of the device , and can realize the gating function of multi-channel signals.

Description of the drawings

Figure 1 is a schematic diagram of the overall structure of a multi-pole multi-throw switch based on an RF MEMS switch provided by an embodiment of the present invention;

Figure 2 is a top view of the overall structure of a multi-pole multi-throw switch based on an RF MEMS switch provided by an embodiment of the present invention;

Figure 3 is a schematic diagram of the switch structure of a multi-pole multi-throw switch based on an RF MEMS switch provided by an embodiment of the present invention;

Figure 4 is a top view of the switch structure in a multi-pole multi-throw switch based on an RF MEMS switch provided by an embodiment of the present invention;

Figure 5 is a schematic structural diagram of an upper electrode cantilever beam in a multi-pole multi-throw switch based on an RF MEMS switch provided by an embodiment of the present invention;

Figure 6 is a schematic structural diagram of a driving electrode provided by an embodiment of the present invention;

Figure 7 is a schematic structural diagram of a power splitter provided by an embodiment of the present invention;

Figure 8 is a schematic structural diagram of an air bridge in a multi-pole multi-throw switch based on an RF MEMS switch provided by an embodiment of the present invention;

Figure 9 is a top view of the air bridge in a multi-pole multi-throw switch based on an RF MEMS switch provided by an embodiment of the present invention;

Figure 10 is a schematic diagram of a four-pole four-throw switch based on an RF MEMS switch provided by an embodiment of the present invention;

Figure 11 is a diagram showing the insertion loss simulation results of a four-pole four-throw switch based on an RF MEMS switch provided by an embodiment of the present invention;

Figure 12 is a diagram showing the isolation simulation results of a four-pole four-throw switch based on an RF MEMS switch provided by an embodiment of the present invention;

Figure 13 is a diagram showing the standing wave ratio simulation results of a four-pole four-throw switch based on an RF MEMS switch provided by an embodiment of the present invention.

Implementation

The present invention will be described in further detail below with reference to specific examples, but the implementation of the present invention is not limited thereto.

Example

Please refer to Figures 1 and 2. Figure 1 is a schematic diagram of the overall structure of a multi-pole multi-throw switch based on an RF MEMS switch provided by an embodiment of the present invention. Figure 2 is a schematic diagram of a multi-pole multi-throw switch based on an RF MEMS switch provided by an embodiment of the present invention. Top view of the overall structure of the multi-pole multi-throw switch. The multi-pole multi-throw switch based on the RF MEMS switch includes a substrate 10 and two MEMS single-pole multi-throw switches 20. The two MEMS single-pole multi-throw switches 20 are arranged on the substrate 10, and the two MEMS single-pole multi-throw switches 20 levels Union.

Each MEMS single-pole multi-throw switch 20 includes a number of signal lines 21 , a ground line 22 , a number of upper electrodes 23 , a number of drive electrodes 24 , a power divider 25 and a number of air bridges 26 . Among them, several signal lines 21 and several driving electrodes 24 are distributed on the surface of the substrate 10. The number of signal lines 21 is the same as the number of driving electrodes 24. One signal line 21 corresponds to one driving electrode 24, and each driving electrode 24 drives a Signal lines 21; ground lines 22 are arranged on both sides of several signal lines 21. The signal lines 21 are led out from the ground lines 22 to isolate the ground lines 22 on both sides. At the same time, the ground lines 22 are arranged on the peripheral side of the driving electrode 24. , one end of the driving electrode 24 is surrounded, so that the ground wires 22 on both sides of the driving electrode 24 are in a connected state; the power splitter 25 is arranged on the substrate 10 and is at a certain distance from the end of each signal line 21, that is, That is, the power divider 25 is disposed at the end of all signal lines 21 so as to be at a certain distance from each signal line 21; the end of each driving electrode 24 is located between the end of each signal line 21 and the power divider 25. There is a certain distance between the driving electrode 24 and the end of the signal line 21 and the power divider 25, that is, the driving electrode 24 is not in contact with the signal line 21 and the power divider 25; the number of the upper electrodes 23 is different from the signal line. The number of 21 and the number of driving electrodes 24 are the same. Each upper electrode 23 corresponds to a signal line 21 and a driving electrode 22. Each upper electrode 23 is provided on the power divider 25 and is located at each signal line 21 and each driving electrode. Above the electrode 24; two MEMS single-pole multi-throw switches 20 are connected through a power splitter 25; each air bridge 26 is located on the surface of the ground wire 22 and spans the signal line 21, so that the air bridge 26 connects the ground wires on both sides of the signal line 21 22 connections.

Specifically, the substrate 10 serves as the carrier structure of the multi-pole multi-throw switch, carrying two MEMS single-pole multi-throw switches 20; the shape of the substrate 10 is a rectangular parallelepiped, and its materials include but are not limited to ceramics, glass, and high-resistance silicon. The materials of the signal line 21, the ground line 22, the upper electrode 23, the driving electrode 24, the power splitter 25 and the air bridge 26 include but are not limited to gold, aluminum, platinum, etc.

The number of signal lines 21, driving electrodes 24, and upper electrodes 23 is at least two, such as 2, 3, 4, etc.; in this embodiment, the number of signal lines 21, driving electrodes 24, and upper electrodes 23 are all 4. indivual. Furthermore, the signal lines 21 adopt a bending structure at the crossing position of the air bridge 26 so that the ends of the plurality of signal lines 21 all point to the power splitter 25 .

In a specific embodiment, the ground lines 22 are equally spaced on both sides of the signal line 21 , that is, the distances between the edges of the ground lines 22 and the edges of the signal lines 21 are equal.

Please refer to Figures 3, 4 and 5. Figure 3 is a schematic diagram of a switch structure in a multi-pole multi-throw switch based on an RF MEMS switch provided by an embodiment of the present invention. Figure 4 is a schematic diagram of a multi-pole multi-throw switch based on an RF MEMS switch provided by an embodiment of the present invention. A top view of the switch structure in the multi-pole multi-throw switch of the RF MEMS switch. Figure 5 is a schematic structural diagram of the upper electrode cantilever beam in the multi-pole multi-throw switch based on the RF MEMS switch provided by an embodiment of the present invention.

In this embodiment, the upper electrode 23 and the driving electrode 24 together form a switch structure.

The upper electrode 23 includes an upper electrode cantilever beam 231, a first anchor point 232, at least two contact points 233 and a first release hole array 234, wherein the first anchor point 232 is provided on the power splitter 25, and at least two Contacts 233 are arranged at intervals on the surface of the signal line 21. Each signal line 21 is provided with a contact 233. The upper electrode cantilever beam 231 is arranged on the first anchor point 232 and is located above the contact 233. The first release The hole array 234 is distributed on the upper electrode cantilever beam 231.

In this embodiment, the use of multiple contacts 233 can effectively enhance the contact between the upper electrode 23 and the contacts 233, and avoid reliability problems of the MEMS switch caused by virtual junctions. The more contacts 233, the more reliable the MEMS switch will be. However, the greater the number of contacts 233, the larger the size of the device. Therefore, considering the reliability of the MEMS switch and the size of the device, the number of contacts 233 is preferably 2, that is, a double-contact structure is used. Specifically, the shape of the contact 233 includes but is not limited to a cuboid, a cylinder, a hemisphere, a cone, etc.

In a specific embodiment, the first release hole array 234 includes a plurality of first release holes distributed in an array. The number of rows of the first release hole array 234 is 1 to 6 rows, and the number of columns is 1 to 8 columns. Each row Or the spacing of the first release holes in each row is 4-8 μm, and the diameter of each first release hole is 4-10 μm.

Please refer to Figures 5 and 6. Figure 6 is a schematic structural diagram of a driving electrode provided by an embodiment of the present invention. The driving electrode 24 includes an electrode 241, a lead wire 242 and a pad 243, wherein the electrode 241 is located between the end of the signal line 21 and the power splitter 25 and below the cantilever beam 231; one end of the lead wire 242 is connected The other end of the electrode 241 is connected to the pad 243 to realize the interconnection between the electrode 241 and the pad 243; the ground wire 22 is located on both sides of the lead wire 242 and surrounds the pad 243, so that The ground lines on both sides of the driving electrode 24 are grounded together.

Specifically, the pad 243 has a rectangular structure. The electrode 241 may be a rectangular parallelepiped or a convex structure. Preferably, the electrode 241 has a convex-shaped structure, and the protruding part of the convex-shaped structure is located between the two contacts 233 . It can be understood that when the contacts 233 adopt a double-contact structure, the signal lines below the two contacts 233 have a concave-shaped structure. At this time, the protruding parts of the convex-shaped electrodes 241 match the concave-shaped structure. The electrode 241 adopts a convex-shaped structure to increase the area of the driving electrode and reduce the driving voltage.

Please refer to FIG. 7 , which is a schematic structural diagram of a power splitter provided by an embodiment of the present invention. The power divider 25 includes a plurality of first branches 251 and a second branch 252. The plurality of the first branches 251 and the second branches 252 form a star structure. The plurality of the first branches 251 correspond to the plurality of signal lines 21 one by one. Two MEMS single poles have multiple The throw switch 20 is connected through the second branch 252 .

In this embodiment, the number of first branches 251 is the same as the number of signal lines 21. Each signal line 21 corresponds to a first branch 251, and multiple first branches 251 and second branches 252 together form a star structure; specifically, , the included angle formed by two adjacent branches may be equal or unequal. Preferably, the included angle formed by two adjacent branches is equal. For example, when the number of signal lines 21 is 4, the number of first branches is also 4, and the four first branches 251 and the second branches 252 together form a star structure. The angle between two adjacent branches is is 72°.

Further, the two MEMS single-pole multi-throw switches 20 are connected through the second branch 252, so that the two MEMS single-pole multi-throw switches 20 form a mirror structure.

Please refer to Figures 8 and 9. Figure 8 is a schematic structural diagram of an air bridge in a multi-pole multi-throw switch based on an RF MEMS switch provided by an embodiment of the present invention. Figure 9 is a schematic diagram of an air bridge based on an RF MEMS switch provided by an embodiment of the present invention. Top view of the air bridge in the switch's MPMT switch. The air bridge 26 includes a fixed cantilever beam 261 , a second anchor point 262 , a third anchor point 263 and a second release hole array 264 , wherein the second anchor point 262 is disposed on the ground line 22 and is located on one side of the signal line 21 , the third anchor point 263 is set on the ground line 22 and is located on the other side of the signal line 21, the fixed cantilever beam 261 is set on the second anchor point 262 and the third anchor point 263 to span the signal line 21, the second The release hole array 264 is distributed on the surface of the fixed cantilever beam 261.

In this embodiment, an air bridge across the signal line is provided on the surface of the ground wire to connect the ground wires separated by the signal wire to achieve common grounding of the ground wires.

In a specific embodiment, the air bridge 26 may or may not be provided above the driving electrode 24 and the second branch 252 . Preferably, no air bridge 26 is provided above the driving electrode 24 and the second branch 252 .

In a specific embodiment, the second release hole array 264 includes a plurality of second release holes distributed in an array. The number of rows of the second release hole array 264 is 1 to 6, and the number of columns is 1 to 12. Each row Or the spacing between the second release holes in each row is 6-10 μm, and the diameter of each second release hole is 6-10 μm.

Please refer to FIG. 10 , which is a schematic diagram of a four-pole four-throw switch based on an RF MEMS switch according to an embodiment of the present invention. Taking a four-pole four-throw switch as an example, at this time, the number of signal lines 21, the number of upper electrodes 23, the number of driving electrodes 24, and the number of first branches 251 in each MEMA single-pole multi-throw switch are all 4, of which one The four signal lines 21 of the MEMA single-pole multi-throw switch serve as the four input terminals of the radio frequency signal RF in, namely Port1, Port2, Port3, and Port4. The four signal lines 21 of the other MEMA single-pole multi-throw switch serve as the four output terminals Port5 and Port4. Port6, Port7, Port8, output radio frequency signal RFout.

Specifically, when the driving electrode 24 applies a driving voltage, the upper electrode 23 is affected by the electrostatic force, causing the upper electrode 23 to bend toward the signal line 21 and contact the contact 233. At this time, a certain MEMS The switch is in the conducting state; when driving voltage is applied to the driving electrodes 24 on both sides of the four-pole four-throw switch respectively, the four-pole four-throw switch is in the conducting state, and the input signal is output by the path through which the switch is conducted; when the driving voltage is removed , the upper electrode 24 is reset, and the MEMS switch is in the off state.

Please refer to FIG. 11 , which is a diagram showing the insertion loss simulation results of a four-pole four-throw switch based on an RF MEMS switch according to an embodiment of the present invention. As can be seen from Figure 11, in the frequency range from DC to 26.5GHz, the insertion loss is better than 1.19dB.

Please refer to Figure 12. Figure 12 is a diagram showing the isolation simulation results of a four-pole four-throw switch based on an RF MEMS switch according to an embodiment of the present invention. As can be seen from Figure 12, in the frequency range from DC to 26.5GHz, its isolation is excellent at 31.75dB.

Please refer to Figure 13. Figure 13 is a diagram showing the standing wave ratio simulation results of a four-pole four-throw switch based on an RF MEMS switch according to an embodiment of the present invention. As can be seen from Figure 13, in the frequency range of DC to 26.5GHz, its standing wave ratio is less than 1.7.

The multi-pole multi-throw switch of this embodiment is cascaded by two MEMS single-pole multi-throw switches. The contacts adopt a multi-contact structure. The upper electrode cantilever beam is fixed on the signal line through the first anchor point, combined with a star power divider. , the design of a four-pole four-throw switch based on MEMS is realized; using a MEMS switch as the main body of the device can effectively reduce the insertion loss of the device, improve the isolation of the device, reduce the size of the device, and broaden the operating frequency of the device. By cascading two MEMS single-pole multi-throw switches, the gating function of multi-channel signals can be realized.

The above content is a further detailed description of the present invention in combination with specific preferred embodiments, and it cannot be concluded that the specific implementation of the present invention is limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, and all of them should be regarded as belonging to the protection scope of the present invention.

Claims (9)

1. A multi-pole multi-throw switch based on RF MEMS switch, which is characterized by including: substrate(10); Two MEMS single-pole multi-throw switches (20) arranged on the substrate (10) and connected in cascade; The MEMS single-pole multi-throw switch (20) includes a number of signal lines (21), a ground line (22), a number of upper electrodes (23), a number of drive electrodes (24), a power divider (25) and a number of air bridges (26 ), wherein the plurality of signal lines (21) and the plurality of driving electrodes (24) are distributed on the surface of the substrate (10), and the ground line (22) is located on the substrate (10) And is arranged on both sides of the plurality of signal lines (21) and the peripheral side of the driving electrode (24), the power splitter (25) is arranged on the substrate (10), the power splitter (25) includes a plurality of first branches (251) and a second branch (252). The plurality of first branches (251) and the second branches (252) form a star structure. The plurality of first branches (251) ) is connected to each of the signal lines (21), the two MEMS single-pole multi-throw switches (20) are connected through the second branch (252), and the end of each driving electrode (24) is located on each Between the signal lines (21) and the power divider (25), each upper electrode (23) is provided on the power divider (25) and is located on each of the signal lines (25). 21) and above each of the driving electrodes (24), two of the MEMS single-pole multi-throw switches (20) are connected through the power divider (25), and each of the air bridges (26) is located on the The ground line (22) is on the surface and crosses the signal line (21). 2. The multi-pole multi-throw switch based on the RF MEMS switch according to claim 1, characterized in that the number of the plurality of signal lines (21), the number of the plurality of upper electrodes (23), the number of the plurality of driving The number of electrodes (24) is four. 3. The multi-pole multi-throw switch based on the RF MEMS switch according to claim 1, characterized in that the signal line (21) adopts a bending structure at the crossing position of the air bridge (26). 4. The multi-pole multi-throw switch based on RF MEMS switch according to claim 1, characterized in that the upper electrode (23) includes an upper electrode cantilever beam (231), a first anchor point (232), at least two contacts (233) and a first release hole array (234), wherein, The first anchor point (232) is arranged on the power divider (25), the at least two contacts (233) are arranged on the signal line (21) at intervals, and the upper electrode cantilever beam (233) is 231) is provided on the first anchor point (232) and is located above the contact point (233), and the first release hole array (234) is distributed on the upper electrode cantilever beam (231). 5. The multi-pole multi-throw switch based on the RF MEMS switch according to claim 4, wherein the first release hole array (234) includes a plurality of first release holes distributed in an array, and the first release hole array (234) The number of rows of the release hole array (234) is 1 to 6, and the number of columns is 1 to 8. The spacing between the first release holes in each row or column is 4-8 μm. Diameter is 4-10μm. 6. The multi-pole multi-throw switch based on RF MEMS switch according to claim 4, characterized in that the driving electrode (24) includes an electrode (241), a lead wire (242) and a bonding pad (243), wherein , The electrode (241) is located between the end of the signal line (21) and the power splitter (25) and below the cantilever beam (231); One end of the lead-out wire (242) is connected to the electrode (241), and the other end is connected to the bonding pad (243). 7. The multi-pole multi-throw switch based on RF MEMS switch according to claim 6, characterized in that the electrode (241) is a convex-shaped structure, and the protruding part of the convex-shaped structure is located at the contact point (241). 233). 8. The multi-pole multi-throw switch based on RF MEMS switch according to claim 1, characterized in that the air bridge (26) includes a fixed cantilever beam (261), a second anchor point (262), a third Anchor points (263) and a second release hole array (264), wherein, The second anchor point (262) is provided on the ground wire (22) and is located on one side of the signal line (21), and the third anchor point (263) is provided on the ground wire (22) On the other side of the signal line (21), the fixed cantilever beam (261) is provided on the second anchor point (262) and the third anchor point (263) to span all The signal line (21) and the second release hole array (264) are distributed on the fixed cantilever beam (261). 9. The multi-pole multi-throw switch based on the RF MEMS switch according to claim 8, wherein the second release hole array (264) includes a plurality of second release holes distributed in an array, and the second release hole array (264) The number of rows of the release hole array (264) is 1 to 6, and the number of columns is 1 to 12. The spacing between the second release holes in each row or column is 6-10 μm. Diameter is 6-10μm.